A device of the above-mentioned class is described in WO 2006/128519. An ignition tube connects a detonation chamber inside a work piece with a gas supply, exhaust, and ignition device, wherein the ignition device is integrated in the ignition tube. The gas, oxyhydrogen in stoichiometric mixture with low oxygen excess, is ignited by the ignition tube arranged in the ignition device. The explosion of the gas develops a detonation wave, which forms the work piece and then wanes.
Experience with similar devices has shown that the ignition device and/or the ignition mechanism get damaged by the explosive forming.